The present invention relates generally to operations wherein a subterranean well is drilled and completed and, in a preferred embodiment thereof, more particularly provides a method and associated apparatus for drilling and completing a subterranean well.
It is well known in the art to drill an initial "parent" wellbore, and then to drill at least one "lateral" wellbore, that is, a wellbore intersecting and extending outwardly from the parent wellbore. Many methods and apparatus for drilling the lateral wellbore and for completing the parent and lateral wellbores have been conceived. For example, U.S. Pat. No. 4,807,704 to Hsu et al., discloses an apparatus and method wherein a whipstock is positioned in a cemented and cased parent wellbore to guide milling and drilling bits for forming the lateral wellbore, and the whipstock is then replaced with a guide member attached via a sealed conduit to a dual string packer. The guide member is utilized to guide a tubing string into the lateral wellbore after the guide member has been properly positioned in the parent wellbore and the packer has been set. The disclosure of U.S. Pat. No. 4,807,704 is hereby incorporated herein by this reference.
Unfortunately, the method and apparatus described above, as well as others utilized for the purpose of drilling and completing lateral wellbores, have several problems associated therewith. In general, such methods and apparatus require is many trips into the parent wellbore to position, set, and/or retrieve various items of equipment therein or therefrom, are limited in their ability to perform operations in the lateral wellbore, are limited in their ability to utilize relatively large diameter lateral wellbores and relatively large diameter equipment within those lateral wellbores, and are characteristically inefficient in their operation.
For example, the method disclosed in the above-referenced patent requires a trip into the well to orient and set a packer, a trip to position a whipstock, a trip to retrieve the whipstock, a trip to convey and position a guide member, conduit, and dual string packer, and another trip to install a tubing string and a tubing guide and connector member. Additionally, it must be noted that the tubing string is capable of being guided into the lateral wellbore with only small diameter equipment attached thereto, since the tubing string must pass through a bore of the dual string packer.
As another example of the limitations of known methods, the method disclosed in the above-referenced patent requires any equipment attached to the tubing string to not only pass through a bore of the dual string packer, but also to displace within the parent wellbore side-by-side with the conduit. These space limitations severely restrict the diameter of any equipment which must be positioned in the lateral wellbore attached to the tubing string.
From the foregoing, it can be seen that it would be quite desirable to provide a method and associated apparatus for completing a subterranean well which does not place inordinate size restrictions on equipment to be positioned within a lateral wellbore, and which does not require a large number of trips into the well to accomplish the desired completion, but which is generally economical and efficient in operation, and which provides increased functionality. It is accordingly an object of the present invention to provide such a method and associated apparatus. Other objects, features, and benefits of the present invention will become apparent upon careful consideration of the description hereinbelow.